Aircraft altitude spacing system



Apl'l, 1943- M. J. FINNEGAN AIRCRAFT ALTITUDE SPACING SYSTEM Filed Aug. 29,- 1941 2 sheets-sheet 1 l lllllla @n vf,

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BY /P l l '.ATTORNEY Amin 13, 1943,

(A Vfl M. 'J FINNEGAN AIRCRAFT rvALTITUDE-SRACING SYSTEM Filed Aug. l29, 1941 ALT/T005 //v Fr l 2 Sheets-Sheet 2 INVENTOR ATTORNEY Patented Apr. 13, 1943 UNITED .STATES PATENT foFrlc-:E Y

Y .2,316,411 AIRCRAFT ALTITUDE sPAoING SYSTEM artin J. Finnegan, Glen Rock, N. J., assigner to Bendix Aviation Corporation, South Bend,

Ind., a corporation of Delaware Application August 29, 1941, Serial No. 408,879

' craft by 500 feet. 'This establishes the basis of Claims.

This invention relates to navigation, and more particularly to a system of trafiic control for aircraft. f

As scheduled flights V along the more prominent civil airways are becoming of greater frequency, it has become necessary for flight in different compass directions to be maintained at prescribed altitudes. It has been found out, however, that due to the fact that thepilot of the plane is often preoccupied with the many probv lems concerned with the maintenance of flight,

` obtained.

It is another object ofthe invention to provide an instrument whereby a pilot may be readily advised whether he is in a proper'altitude level ior the direction of ilight being maintained.

Other objects of the invention include the combination .of directional and elevational instruments in a manner to keep a pilot advised of his altitude level, and alsofto indicate, upon either a change of altitude or a change vof heading, when his craft is in correct flight condition.

Other objects will appear from a study of the following specification when made in conjunction with the attached drawings, throughout which like numerals designate like parts.

Fig. 1 is a diagrammatic showing, with parts in perspective, of one embodiment of the present invention.

Fig. 2 is a perspective, showing ilights in four directions atspaced levels; and n Fig. 3 is a representation of a flight altitude schedule representative' of a particular traffic control system.

It is a. requirement of civil aircraft employing the Federal airways, either in scheduled or in non-scheduled flight, that flights in opposite directions must be spaced by an altitude on the order of '1000 feet. Further, the different airlines now ncompel their pilots to observe addi- `tional requirements of 4altitude in certain directions of flight, intended to eliminate the possibility of collisions between aircraft flying in any two directions. i

Having reference to Fig. 2, it will be noted thatthe aircraft designated as I0, II, I2 and I3 are flying in the respective directions of south,

west, north and east, and thatthe flight of each is separated from theflight of the next adjacent an aircraft traic control system, wherein flights in the cardinal directions are spaced at 500 foot levels. A reference to Fig. 3 shows the arrangement of flights in the four cardinal directions for altitudes between 500 and 10,000 feet, andy thsfsystem may be vtaken as an example of a workable trailicfcontrol system upon which the device shown in Fig. 1 is based.

An altimeter I4 has Va conventional pointer member I5 and altitude indicating scale I6, both of which are shown with parts broken away, revealing a contact arm v'I1 which is movable with pointer I5, and sets ofadjacent insulated contact members I8, I9, 20 and 2I which are disposed throughout the circumference of the casing of the altimeter I4. The contact members I8 are connected by means of conductors 22 to a single conductor 23 attached to brush member 24 of the commutator 25. 'Contact members I9 are connected together by means of conductors 26 to a common conductor 21, electrically connected to brush member 28, which is degrees away from brush member 24. Contact members 20 are electrically connected in parallel by means of conductors 29, and to a common conductor 30, attached to brush member 3l spaced 90 degrees away from brush 28 and 180 degrees away from brush 24. Contact members 2l are connected together by means of conductors 32, which are commonly connected to a conductor 33, attached to brush member 34, which is spaced 90v degrees away from each of the brushes 24 and 3I. Contact members I8, I9, 20 and 2I are of edual size, each extending peripherally for a distance equal to 500 feet of altitude indication. It takes a change in altitude of 50G feet, for example, for contact arm I'I to move completely across a contact I8 to an adjacent contact I9. Additional sets of contacts I8, I9, 20 and 2|- are .disposed circumferentially within casing of altimeter I4, but in order to avoid showing a confusing multiplicity of conductors in explanation of the invention, comvat 39, by any conventional means.

Shaft 35 carries a pointer 40, which is rotatable with respect to a conventional azimuth scale 4| at the upper end of shaft 35.

Scale 4I is intended to be fixed to an aircraft (not shown), while pointer 40 is rotatable with respect to scale 4I to indicate the directional heading of the aircraft at all times. Pointer 40 may be rotated under control of an earth inductor compass of the type shown in Fig. 4 of the La Pierre Patent, 2,053,154. In accordance with the teaching of the La Pierre Patent, a permeable core is rotatable about a central vertical axis by means of a torque amplifying motor, so that at all times the core Will be oriented to lie transversely of the north-south axis of the earths field, and a north bearing pointer is utilized to indicate the direction of the earths magnetic field, or when mounted in a craft, the

heading of the craft. Such a permeable member is contained in a housing 42, as shown in Fig. 41 of the present invention, and is fixed to shaft 35 and a two-phase motor 43, which is the counter# part of the two-phase motor shown in the La Pierre patent. One phase winding 44 is connectedlwithin housing 42), in an appropriate manner, to the permeable member, after the teaching of La Pierre. The second phase winding 45 is connected to a source of alternating current of suitable frequency represented schematically as an alternator 46. The armature of motor 43 is connected to a drive shaft 41, carrying a worm gear 48, which mesheswith a Wheel 49, keyed to the lower end of shaft 35.

Scale 4| is shown as being divided, by means of the rectangularly associated lines 62 and 63, into four quadrants or sectors, each including a cardinal azimuth direction, Preferably, each of these sectors, which are labeled N. S." (north sector), E. S." (east sector), S. S. (south sector) and W. S." (west sector). extends 45 degrees on each side of a cardinal heading, for example, the north sector extends from northeast to northwest, and the center line of such sector passes through north. Brush members 34, 24, 25 and 3| lie directly under the scale indications of North, East, South and West, respectively.

It will be seen that at any one time, one of the brush members will be in contact with the insulating sector 38 of armature 25, While the other three will be in contact with the conductive portion 36. Thus, one of the conductors 23, 21, 30 and 33, is always opencircuited in an electrical circuit, which may be traced from a ground 35, commutator 25, parallel conductors 423, 21, 30 and 33, to contact segments i8, I9, 20 and 2i through contact arm i1, conductor 50, solenoid 5|, battery 52 and ground 53. Solenoid 5l is a part of a relay 54, having an iron core member 55 with an integral arm 55. Conductor 50 is connected to Contact arm i1 through any suitable pivot bearing connection.

Scale I6 is provided with a window portion, the outline of which is designated by the closed dashed line 51. A flag member 58 is pivoted at a point 59, and is also connected by means of a loose link 50, to relay arm 56. Flag 56 carries two indications, for example, Change altitude and Altitude correct. When relay 5I is opencircuited or de-energized, flag member 58 is maintained in the position shown by the action oi a. coiled spring member 6I. In this position, the legend Altitude correct" appears in window 51, and the legend Change altitude" is obscured by the opaque face o f scale I8.

From Fig. 1 it will be seen that the .craft is heading north, and contact arm l1 is in engagement with a contact 2i at about 3500 feet. Since conductor 32 connects to conductor 33, it will be seen that brush 34 bears against the insulating sector 38. and thus, the electrical circuit is maintained open, and relay 54 is cie-energized. An inspection of Fig. 3 will show that an altitude of 3500 feet is correct for a course heading of north. Thus, the showing of the indication Altitude correct is in accordance with the system. 1f, however, the airplane should change its heading to west, remaining at 3500 feet, it will be seen that brush 34 then comes in contact with the conductive portion 35, and the electrical circuit containing relay 54 becomes completed, and flag member 58 is moved to the right by the attraction oi' 55 within solenoid 5l, and the warning "Change altitude" appears within window 51. The pilot, upon seeing the warning, merely increases or decreases his altitude until the indication Altitude correct appears at window 51. Assuming that he decreases altitude, this will occur when pointer I1 moves upwardly into engagement with the adjacent contact segment 2l,

and the altitude indication will be 3000 feet.

It will be understood, of course, that when the craft is heading west, insulating sector 55 is in contact with brush Jl so that upon arm l1 coming in contact with contact segment 20, the electrical circuit will become opened, and relay 54 will be de-energized. Had the pilot desired to increase his altitude rather than to decrease it for a westerly heading, he could have gone to 5000 feet, at which time contact arm I1 would again be in circuit with a contact 20, and relay 54 would again become de-energized, allowing flag 55 to show that an altitude of 5000 feet for a westerly heading is correct.

From the above example of navigation in accordance with the particular aircraft trailic control system set forth, it will be readily seen that in Asectors each including a cardinal compass.' direction, the altitudes of aircraft are spaced by. intervals of 500 feet. The chart shown in Fig. 3"" lists the particular aircraft altitudes appropriate foi-,flights in the different cardinal directions up to 10,000 feet, and it is obvious that this aircraft traffic control schedule may be expanded to any altitude level selected.

While the indicating element used in the description of the particular embodiment of the invention set forth in Fig. 1 is shown as indicating flag 58, it is obvious that other indicators, such as buzzers or two-colored lights, may be utilized either with or without a relay system. It is desired, therefore, not to limit the invention to the particular indicator selected for the purpose of description, since many modifications may occur to one skilled in the art in following the teaching of the present invention. The invention is to be limited, therefore, only by the scope of the appended claims.

What is claimed is:

l. A device for indicating a desired flight level of an aircraft` comprising an altimeter, a compass including a directive element having an axis of rotation, a motor, a shaft connected thereto and passing through said axis, a commutator carried by said shaft, a plurality of sets of contacts carried by said altimeter and regularly distributed about the periphery thereof, four brushes in contact with said commutator, said brushes being spaced about said commutator at intervals yof ninety degrees and each lying in a different compass sector, connections between four adjacent of said contacts and each of said brushes, other adjacent contacts being connected in parallel and in the same sequence to each of said brushes, means for closing an electrical connection through different ones of said contacts at different indicated altitudes, a solenoid in circuit with said contacts, brushes and commutator, a source of electrical energy for said solenoid, a flag carrying matter indicating a flight altitude condition, and means connecting said flag and said solenoid, whereby upon a change of heading of the craft from one compass rsector to another, operation of said solenoid will actuate said flag to indicate that a change in altitude level should be made.

2. In a navigational system wherein flights in the cardinal directions are to be at spaced altitudes, a device for indicating an aircraft's compliance or non-compliance therewith, comprising an altimeter having a scale and pointer, a contact arm movable with said pointer, a plurality of sets of contacts radially disposed about said contact arm and engageable therewith, each contact in said set being spaced from other contacts in the same set by a fixed amount, electrical control means in circuit with said contact arm, a source of electrical energy for energizing said control means, an indicating member in circuit with said contact arm, a compass having a directive element aligned in the earths field, a commutator carried by said element, brushes associated with said commutator and lying in compass sectors 90 degrees apart and connections between each set of said contacts and said brushes, whereby said indicating member wili, under supervision of said control means, show the compliance or non-compliance of the craft with the system.

3. In a trailic spacing system for aircraft, a device forindicating an aircrafts compliance or non-compliance therewith, including acompass having a directive element subject to the innuence of the earths magnetic field, an altimeter having a set of contacts regularly spaced lthrough the indicating range of said altimeter, an electrical circuit, an indicator in said circuit, means in circuit therewith for operating said indicator, and electrical connections associated with said circuit and with said compass, so that. upon a cardinal change of azimuth indication by said compass, said indicator will be actuated to show the compliance or non-compliance of a craft with the system.

4. In an air traffic system whereby flights in four sectors of azimuth are to be at spaced altitude levels, a device for indicating the compliance or non-compliance of a craft therewith, including a compass having an element rotatable with respect to the craft in azimuth, a commutator mechanism responsive to rotation of said element, an altimeter having an altitude scale and carrying four sets of contacts, insulated and regularly spaced with respect to the altitude indications of said scale, a relay, a source of electrical energy therefor, a rotatable contact in circuit with said relay and associated with said altim'eter and movable over different ones of said contacts for diiferent fiight altitudes and connections between each of said sets of contacts and said commutator mechanism, whereby, upon a change of compass heading from one of said four sectors to another, said relay will be actuated to show -the compliance or non-compliance of said craft thereof rotatable with respect to said craft for different headings in azimuth, a shaft for rotating said element, a commutator carried by said shaft, brushes associated therewith, connections between each of said sets of contacts and differ-l ent ones of said brushes, 'a solenoid in circuit with said first mentioned brush member, a source of electrical energy therefor, and indicating: means operated by said solenoid to show the compliance or non-compliance of the craft with said system.

MARTIN J. FINNEGAN. 

